1. Field of the Invention
The present invention generally relates to test probes for integrated circuit (IC) sockets, and more particularly to a test probe and a manner of making the test probe for insertion into integrated circuit sockets.
2. Background Information
Integrated circuits are commonly made with sockets for receiving semi-conductor chips. During the production process, these sockets are tested to be sure that all of their electrodes are connected and that they mate correctly with the electrodes of the socket to be inserted. To test the IC socket, a test probe is inserted into the socket. The test probe has electrodes which make contact with the electrodes of the socket. The electrodes of the test probe are connected to a testing device which can perform diagnostic testing of the socket and its relation to other circuitry in the IC. These sockets are typically mounted on printed circuit boards (PCB) and many such devices are connected to each other by circuitry in the PCB. An individual socket test probe is inserted into a large number of sockets to be tested during the lifetime of the test probe. These repeated insertions and removals cause wear on the electrodes of the test probe, and finding a design of a socket test probe which provides reliable connections, and durability after repeated insertions, is an ongoing problem. As the number of electrodes in these sockets has increased, the electrodes have become smaller and the spacing between them has also become closer. Therefore, the electrodes of the socket test probe must also be tightly packed together, and yet remain completely isolated from neighboring electrodes, accurately placed, small in width, and extremely durable. Achieving these goals has been difficult in prior art electrodes.
One socket test probe which attempts to resolve this problem is that of Tan, U.S. Pat. No. 5,436,570. Tan utilizes metal pins embedded in resin as the electrodes of a probe head. The sides of the probe head are machined so that the pins are partially exposed. The partially exposed sides of the pins form the electrodes of the probe head. According to Tan, the pins are to be machined so that less than fifty per-cent of their diameter is machined away. In actual practice, it is not uncommon for more than fifty per cent of a pin to be ground through. When this happens, the remaining portion of the pin is not very strongly held in the surrounding resin. After repeated uses, a pin can come loose from the resin and be peeled away from the probe head, and further use of that probe head will damage the sockets being tested.
Accordingly, it is an object of the invention to provide a socket test probe which has the capability of simulating narrow, closely spaced electrodes, but which will be durable for multiple insertions, and is not highly sensitive to machining errors during production.
A further object is a socket tester in which the electrodes do not become dislodged from the probe head and peel away from it.
Another object of the invention is to provide a process for making such a socket probe tester.
A further object of the invention is to provide a socket probe tester with the capability of renewing its electrode surfaces when they show wear.
Additional objects, advantages and novel features of the invention will be set forth in part in the description as follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.